As you know a migrating from Configuration Manager 2007 to Configuration Manager 2012 is a side by side migration. Using the Migration Feature in Configuration Manager 2012 migrates almost all of your objects from Configuration Manager 2007 to Configuration Manager 2012. When migrating objects with a source, like packages, the source is not automatically migrated to a new location. Coretech created a freeware communuty tool called the “Coretech Package Source Changer 0.3.0.0” that will help you change the location of the package source. Let’s see how we can use this nice tool, that is already around for a while.
Read the complete blog here: http://www.systemcenterblog.nl/2012/05/23/migration-to-configmgr-2012-how-to-migrate-the-package-source/